Depending on the move choice, that set falters against Taunters, Azelf in particular. I think Thunder Wave is expendable, so you can use Thunderbolt to give you at least a chance against those kinds of leads. Alternately, you can use Discharge if you feel lucky with your paralysis chances. Keep Quick Attack in the last slot.
The only reason to use Plusle over Minun is to use the more powerful Grass Knot to cover Swampert and Hippo, which isn't a half-bad idea, especially against the latter's SS ruining your Sash. You outrun Roserade, but there is sadly little you can do to it.
I'm all for fun sets, and that certainly does look fun. :) Plusle/Minun can beat Swampert, Aerodactyl, Jirachi (nearly all lead ones are physical and you can stall out Trick's PP with Copycat if it stays in; if you force it out, you've prevented its set-up which is still helpful), Metagross, and lolNinjask but falters against most other leads. You can't beat everything though, so if it works for you, keep using it.